NO ONE voted for the biggest winner in yesterday’s runoff — the Working Families Party.

With only 11,800 members here, the left-leaning, union-backed party wielded its organizing muscle in a low-turnout election to help elect candidates certain to assume two of the city’s three citywide offices, John Liu as comptroller and Bill de Blasio as public advocate.

Political insiders are already talking about de Blasio, the WFP’s closest ally in government, as a mayoral contender in 2013.

“What they’re looking to do is position de Blasio to be the mayor,” said one veteran political consultant. “There’s no debate.”

Earlier this month, the WFP backed four of the five challengers who ousted incumbents in the City Council.

The payoff: The party and its union affiliates will influence decisions in every sector of city government, except the mayor’s office, assuming Mike Bloomberg wins a third term.

“They are not doing this for holy reasons. They’re waiting for their piece of the pie. They’re going to be eating it for the next four years,” said City Councilman Simcha Felder (D-Brooklyn).

That could leave a sour taste in the mouths of New Yorkers looking for a government that more evenly balances the needs of municipal workers and taxpayers, especially those in higher-income brackets.

In Albany, the WFP was the driving force pushing the state Legislature to increase the state income tax on residents earning $300,000 or more a year.

“They’re going to put pressure to do the same thing here [for the city income tax],” predicted one WFP critic.

With a more powerful WFP, Bloomberg faces a much rockier road trying to push through lower pension benefits for new city employees. Unions already have an outsize role in government.

The WFP’s ability to pull out the vote for its selected candidates increases that clout considerably, raising the question of how many elected officials are going to be willing to take on an issue in the public interest if it’s not in the WFP’s interest.